58

USES.

The use of sodium carbonate in the industries has increased very
greatly in the last thirty years and in North America the war caused a
further increase in production and price, as indicated in the table page 57,
Sodium salts have been used in the making of munitions and as substitutes
for potassium compounds in the manufacture of glass, soap, matches, and
cyanide in photography, medicine, and tanning. Soda ash is used very
widely in nearly all of the chemical industries, especially in making dye-
stuffs and oxplosives. It is used directly in glassmaking and as sodium
hydroxide in the wood pulp and soap industries. Sodium bicarbonate is
used in medicine, in cooking, and for making éffervescent drinks.

\ OCCURRENCES IN THE DISTRICT.

The soda lakes examined during the course of this work all lie within
the Green Timber plateau, north of Clinton. The plateau is a comparatively
flat tract of country covered with glacial drift in which large basalt boulders
predominate. Near the edges of the plateau, as at the deep canyon known
as the Chasm near 59 Mile House, the plateau surface may be seen to be
underlain by several hundred feet of flat-lying basaltic flows and it is
presumed that the topography of the plateau in general, is due to such
basalt beds. The soda lake basins are ustially landlocked, are filled with
brines of varying strength, and their shore-lines are rimmed with a white '
crust. The stronger brines have an unpleasant odour. They seem devoid
of plant life, but many of them contain a small red crustacean, presumably
the alkali shrimp (artemia gracilis); and swarms of black flies (Ephydra),
a little larger than the common housefly, congregate on and under the salt
crust on which they seem to exist. The bottoms of these lakes are covered
with soft, sticky, blue clay.

One of the lakes, the Last Chance (Plate XI), contains a brine that
is, apparently, nearly saturated and a network of salt circles was observed
similar to that occurring in the spotted epsomite lakes at Clinton and
Kruger mountain. The rings are from 10 to 15 feet in diameter near the
edge of the lake and appear to be much wider in the middle of the lake.
Between the rings are cusp-shaped spaces occupied by mud ridges rising
2 to 6 inches above the salt circles. Near the edge of the water these
ridges are above water-level, and the rings, in places, are covered with
several inches of water. Boulders, many of them from 6 inches to a foot _
in diameter, lie on these ridges. A circle of salt near the edge of the lake
was found to lie on black mud. The rings of salt have the same surface
appearance as those in the epsomite lake at Clinton, page 51, and the
characteristic cone-shaped salt bodies may be present nearer the lake centre
which was inaccessible because of the extremely soft, unstable mud bottom.

Composition.

' The composition of the salts obtained from three lakes and of the
brines from two is given in the following tables. The analysis of the salt
dug from under the brine in Goodenough lake, Table VIII, No.2, indicates
a salt composed of about 97 per cent of natron, NaeCO;.10H.O, with ~
less than 1 per cent of sodium hicarbonate, and some water in excess.